I'm a bit of a noob when it comes to engine building so please forgive...I've doen a lot of searching and haven't found all the answers yet.

Some background -
I just picked up a '69 chevelle basket case frame off resto never finished by previous owner.

Included is a 350 built by a very good local machine shop several years ago. He included the engine build sheet that gave me some detail on the build:
-bored and honed with torque plate (assuming 30 over but haven't confirmed yet
-forged pistons - not sure on style or CR
-crank journals were ground
-ported cast iron heads (don't have the engine at home to get casting numbers yet)
-Edelbrock 2101 intake
-crane 100072 hyd flat tappet cam (I believe that is the PN, sheets are at home and I will confirm later)
-engine dynoed at 360HP and about 400TQ
-owner claims about 5000km on the motor but since it was built in '96 I'm a bit skeptical (although the car has been torn down for about 4 years)

I plan on eventually building or buying a big block but that will be a few years off. In the meantime I'm considering opening the motor up to check it out since I have plenty of time over the winter while the body work is being done. I'm assuming that even if it has been bored 30 over already I will need to swap pistons to 383 specific ones so I will have to re-hone the cylinders, correct? This is somewhat of a waste of the existing forged pistons but the pins are not located correctly fo rth elonger stroke crank correct? I should be able to re-use the 5.7" rods as long as I'm willing to externally balance right? Then it should just be a matter of picking up a 350main 383 crank and checking rod clearances? I have read that the required clearancing of the block is minor and can be done at home with a die grinder...I'm tempted to go this way since this will be a 1-2 summer motor until my BB is ready and I'm treating it as more of a learning project to see if I want to build my own motor later.

I have been checking out the scat cranks but I'm not sure which series to go for in this application...likely no more than 6000rpm and mostly street use with a few strip runs. I may try playing with some spray when i'm almost ready to swap motors just for fun. Any piston and cam recomandations? I understands you can get away with about 10 degrees more duration on a 383 vs a 350? Would leaving the current cam in be a big mistake? Will I be giving up huge amounts of power by staying with the ported cast heads (I realise you would need casting numbers to really answer this).

Thanks a lot and sorry about so many questions.

I suggest that you get yourself the proper measurment tools before attempting the build. Such as a dial bore gauge, a venier caliper, some micrometers (from 1"-2", 2"-3", etc.) along with an inside mic, and a torque wrench to start.

As long as all the cylinders are within range (no more then 2-3 thousandths of each other), you don't have to over bore the cylinder. You can simply do a quick/nice re-hone yourself, and your cylinders are good to go :) So yes, you're correct in having to swap out the 350 pistons for some stroker ones. As for the rods, I'm not too sure on that one, but there are others who will help you out there. As for "loosing out" on those 350 pistons, sell them and recoupe some of your money. Or, ask the guy your buying the stroker pistons from, and see if he'll knock the price down on the new pistons in exchange for the forged ones. As for the crank, shop around. You can pick up a nice nodular crank at a decent price. As for the heads, no matter what, stock GM heads are restrictive no matter what.....BUT, of course, GM did make some heads that flowed a lot better then others (such as the smog heads). If you're going for all out power, it's a better idea to get yourself some good aftermarket heads. But if the motor is going to be used once in a while with a few passes at the track, then (depending) the current heads you have right now might be ok. I hope I've been of some help :) Good luck on your build and have fun! :D